1. Field of the Invention
The present invention relates to a polysaccharide blend composition, preferably polygalactomannans which includes both cationic and anionic materials. More specifically, the blend composition includes a polysaccharide containing sulfonated anionic groups which are preferably derived from ethylenically unsaturated monomers including one or more sulfonate groups. The resulting compositions exhibit enhanced viscosities as compared to the viscosities obtained when using the cationic and anionic polysaccharides separately or as compared to the viscosity of using nonionic polysaccharides or other anionic/cationic polysaccharide blend combinations.
2. Technology Description
Natural and synthetic gums have been used as thickeners for foods, coatings, paints, explosive slurries, oil well fluids, cosmetics, and many other functional applications. One class of gums that have been widely used as suspending and viscosity agents are polygalactomannans. Polygalactomannans are polysaccharides composed principally of galactose and mannose units and are usually found in the endosperm of leguminous seeds such as guar, locust bean, honey locust, flame tree, and the like. In practice, to thicken a fluid the polygalactomannans may either be added by themselves, or with other viscosity modifiers such as other polygalactomannans, xanthan gum and the like.
U.S. Pat. No. 3,467,647 disclose polysaccharides containing both cationic and anionic substituents. Amongst the starting polysaccharides which are then modified according to this patent include starches, locust bean gum (carob gum) and guar gum. Cationic substituents include primary, secondary, or tertiary amino groups or quaternary ammonium, sulfonium or phosphinium groups. Suggested anionic substituents include carboxyl, sulfonate, sulfate or phosphate groups. Example 9 of this patent discloses guar gum as the polysaccharide, trimethylammoniumhydroxypropyl as the cationic groups, and phosphates as the anionic groups. The degree of substitution for each of these groups in this example is 0.05.
Similarly, DD 281966 discloses a gel former which has-both cationic and anionic polymers and provides a synergistic increase in viscosity as compared to solutions which contain separate amounts of the polymers. The cationic polymer is preferably a poly(dimethyl-diallylammonium chloride) containing pyrrolidinium units and the anionic polymer is preferably carboxymethylcellulose with a degree of substitution of 0.6-1.2.
U.S. Pat. Nos. 4,264,322; 4,403,360 and 4,454,617 disclose dye compositions for textile fibers. The compositions comprise an admixture of immiscible gel phases, wherein one gel phase is thickened with a cationic gelling agent and wherein a second gel phase, which is dispersed in the first gel phase, is thickened with an anionic gelling agent. Suggested cationic gelling agents for the first phase include cationic polygalactomannans containing quaternary ammonium ether substituents. Suggested anionic gelling agents for the second phase include hydrocolloids which have the same type of basic polymeric structure as the cationic gelling agents, except that in place of the cationic group there is substituted an anionic group such as a carboxylic acid, sulfonic acid, or sulfate.
A number of references disclose polygalactomannans containing different substituents. None of these references disclose or suggest that these substituted polygalactomannans be combined with other polygalactomannans to yield a superior viscosity modifying composition. For example, DE 1,518,731 discloses that galactomannans or glucomannans may be etherified with .beta.-halogen ethane sulfonic acid or halogen methane sulfonic acids in the presence of base to yield compositions which can function as textile finishes, sizes and print thickeners.
U.S. Pat. No. 3,912,713 and FR 2,242,401 disclose guar gum derivatives and processes for preparing the derivatives. The derivatives are prepared by adding a substituent to guar gum splits in the presence of water, and typically, base. Amongst the substituents (derivatizing agents) suggested for use in these patents are haloalkylsulfonic acids, such as bromoethanesulfonic acid and chlorohydroxypropanesulfonic acid, epoxyalkyl sulfonic acids, such as epoxypropane sulfonic acid, and .alpha.,.beta.-alkylene sulfonic acids, such as ethylene sulfonic acid. These compounds are suggested for use as thickening agents, stressing, sizing and finishing agents, protective colloids and as agents for stabilizing dispersions and emulsions.
U.S. Pat. No. 4,031,305 discloses sulfohydroxypropyl ethers of polygalactomannans having a degree of substitution between about 0.01 and 3. The ethers are prepared by contacting solid guar gum or locust bean gum with a 3-halo-2-hydroxypropanesulfonic acid or acid salt in the presence of base. The galactomannan ethers are alleged to be anionic in nature and are proposed for use in petroleum, textile, printing, paper, food and pharmaceutical industries.
U.S. Pat. No. 4,057,509 discloses the formation of an acidic gel by contacting a polygalactomannan with an allyl halide, followed by exposing the formed polygalactomannan allyl ether material to a stream of sulfur dioxide. The gels are suggested for use in oil well drilling mud compsitions and oil well fracturing compositions.
Borchardt, "Viscosity Behavior and Oil Recovery Properties of Interacting Polymers", Water-Soluble Polymers, pp. 446-465, 1991, (Chem. Abstracts CA115(16):16250p) discusses the use of certain polymer combinations which provide enhanced viscosities as compared to the viscosities of the individual polymers. Combinations mentioned include poly(styrene sulfonate) and either xanthan gum or hydroxyethyl cellulose, poly(vinyl sulfonate) and Xanthan gum, a quaternary-ammonium-salt modified guar and either hydroxypropyl guar or hydroxyethyl cellulose, and a sulfonated guar (D.S. of 0.10; chemical name not mentioned) and either hydroxyethyl cellulose or carboxymethylhydroxyethyl cellulose. These combinations are suggested for use in oil recovery.
U.S. Pat. Nos. 5,132,284 and 5,132,285 disclose neutrally charged polyamphoteric polysaccharide graft copolymers. The references suggest that guar gum or a derivative of guar gum may be used as the base polysaccharide and that the polymer chain includes grafted cationic and anionic substituents. These materials are suggested for use in oil field applications.
Despite the above, there still is a need for compositions which demonstrate enhanced viscosity behavior.